source: chapter07/introduction.xml

trunk
Last change on this file was a8f3814a, checked in by Xi Ruoyao <xry111@…>, 4 months ago

kernfs: technically, they are not needed for chroot

Chroot command itself does not require kernel VFS mounted. You can mount
/proc, /sys, and /run after entering chroot with
"mount -v -t proc proc /proc" etc. For /dev, if the host kernel
supports devtmpfs, you can also mount /dev in chroot with
"mount -v -t devtmpfs devtmpfs /dev". Even if the host does not support
devtmpfs, it's still possible to mount /proc in chroot, then use
"mount --bind /proc/1/dev /dev".

It's just LFS editors decide to mount them before chroot. So reword
some untrue assertions.

  • Property mode set to 100644
File size: 1.5 KB
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1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4 <!ENTITY % general-entities SYSTEM "../general.ent">
5 %general-entities;
6]>
7
8<sect1 id="ch-tools-introduction-chroot">
9 <?dbhtml filename="introduction.html"?>
10
11 <title>Introduction</title>
12
13 <para>This chapter shows how to build the last missing bits of the temporary
14 system: the tools needed to build the various packages. Now
15 that all circular dependencies have been resolved, a <quote>chroot</quote>
16 environment, completely isolated from the host operating system (except for
17 the running kernel), can be used for the build.</para>
18
19 <para>For proper operation of the isolated environment, some communication
20 with the running kernel must be established. This is done via the
21 so-called <emphasis>Virtual Kernel File Systems</emphasis>, which will be
22 mounted before entering the chroot environment. You may want to verify
23 that they are mounted by issuing the <command>findmnt</command> command.</para>
24
25 <para>Until <xref linkend="ch-tools-chroot"/>, the commands must be
26 run as <systemitem class="username">root</systemitem>, with the
27 <envar>LFS</envar> variable set. After entering chroot, all commands
28 are run as &root;, fortunately without access to the OS of the computer
29 you built LFS on. Be careful anyway, as it is easy to destroy the whole
30 LFS system with bad commands.</para>
31
32</sect1>
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